Spark-plug protector.



A. R. BULLOCK.

SPARK PLUG PBOTEGZ'OR.

APPLICATION FILED PEB.29, 1908.

1,009, 43, Patented N ov.21, 1911.

[kn/52mm: 7 fiJza' JM W a A A ARTHUR B. BULLOCK, OF CLEVELAND, OHIO;

SPARK-PLUG rnorno'ron Specification of Letters Patent.

Patented Nov. 21,1911.

Application filed February 29, 1908. Serial No. 418,448.

To all whom it may concern:

Be it knownthat I, ARTHUR R. BULLOCK, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Spark-Plug Protectors, of which the following is a full, clear, and exact description,-reference being had to the accompanying drawings.

, This invention relates to spark plug protectors and has for its object to provide a protecting device for use with spark plugs which will. effectively prevent the deposit of water or other circuit-closing matter on the insulating surface between the core and shell thereof as well as betweenthe device itself and the shell. While a large field for its usefulness will reside in the case of spark plugs which are employed with the engines of motor boats and launches, it is not limited in use to such engines, as conditions may arise wherein it will be useful in connection with the engines of automobiles, as well as with other engines. Y

The objects of the invention are to provide a device of this kind which is simple in construction and which is particularly efiicient and durable in operation. I accomplish these objects by the embodiment of my invention disclosed in the drawings forming a part hereof, where1n- Figure 1 represents a perspective view of a portion of an en ine having a spark plug applied thereto, said spark plug being provided with my protecting device; Fig. 2 represents a vertical sectional view through my protecting device, showing the same ap plied to a spark plug, the latter being represented in elevation; and Fig. ii'represents a bottom plan view of the device and plug shown in Fig. 2.

Describing the parts by reference characters, 1 denotes an engine cylinder into which there is threaded the shell 2 of a spark plug. This plug may be of any approved construction, the one shown comprising an exteriorly threaded shell, to which reference has been made hereinbefore, and a terminal core 3 which is supported within and insulated from said shell. Core 3 is provided with a sleeve 6 of insulating material which is interposed between said core and the clamp nut 7 by means of which the core is secured within the shell.

Generally, where spark plugs are exposed to moisture, as in the case. of their use with motor boats, the presence of moisture on the outside of the insulating sleeve in considerable quantity would form a short circuitbetween the upper or outer end of the core 3, and the nut 7 and easing 2. Furthermore should moisture enter the casing between the nut 7 and sleeve 6, it might produce a short circuit .between the core and the inte rior of the casing, and would causethe parts to corrode. To preventv such occurrences, I provide a protecting device of the type shown in the drawings. This device comprises a metallic body 8, which body is of generally frusto-conical shape, its upper end being of a diameter to receive therein the member ,9 at the upper end of sleeve 6, which may be a nut applied to the outer end of the core'3, and said upper end has a threaded perforation therethrough which is adapted to fit more or less snugly the end of said core. The lower end of body 8 is pro.

vided with a depending cylindrical skirt 10. At the junction of the skirt and tapered body, there is provided an annular recess 11 for the reception of an annular baffle 12, which is of insulating material, as mica. The parts are so proportioned that this baffle will be substantially in the plane ofthe reduced outer end of casing 2,-substantially at the junction of said body and clamp nut 7. The diameter of the central opening in baffle 12 is substantially equal to the diameter of casing 2. At a point above or beyond recess 11, body 8 is provided with a second annular recess 13 in which is fitted a second annular disk 14, which is also of insulating material and is of the sameinternal diameter as disk 12. 15 denotes a third annular disk of insulating material which is interposed between disks 12 and 14, resting on top of the nut 7 and closely fitting sleeve 6. The external diameter of disk 15 is substantially the same as the internal diameters of disks 12 and 14. C

With the parts arranged as described, the operation will be as follows: Any water, such as spray coming on board the boat on which the plug is used,'that strikes on the outer surface of the body 8 will be discharged down and from the outer surface of body 8. Any such water will be intercepted by the bafiles 12, 15 and 14, and can'- not work into the narrow space between sleeve 6 and nut 7. Furthermore, the fact that washers 12, 14 and 15 are spaced apart or discontinuous prevents any short circuiting between core 3, body 8 and shell 2. Furthermore, any water that may pass the lower disk will, by the heat of the parts, be speedily converted into steam and thus be dissipated before sufiicient water can accumulate to cause short-circuiting.

Body 8 will preferably be made of metal. This is advantageous in that the use of-metal prevents the cracking of the bod striking of water upon the heate' surface thereof.

From the foregoing description, it will be seen that I have produced a spark-plug protector which is extremely simple of construction, but which will effectively prevent shortcircuiting of such plugs where the same are exposed to the action of moisture or spray.

Having thus described my invention, I claim:

1. The combination, with a spark plug, of a metallic protecting body adapted to be applied to the outer end of said plug and to inclose the outer end of the shell of said plug, and a ring or annular washer of insulating material carried by said body and projecting inwardly therefrom, substan-. tially as specified.

2. The combination, with a spark plug comprising a core, an insulating sleeve, and a shell, of a protecting body mounted on the outer end of the core and inclosing the outer end of the shell, an annular washer or ring by the of insulating material projecting inwardly from said body toward the outer portion of the shell, and an annular ring of insulating material supported from said shell, substantially as specified. I

3. The combination, with a spark plug comprising a core and a shell, of an ad usting nut for clamping the core to the shell, a protecting body mounted on the outer end of the core and inclosing the outer end of the shell, an annular washer or ring of insulating material pro'ecting inwardly from said body toward sai shell, and an annular washer or rim of insulating material mounted on said ad usting nut and having its external diameter substantially equal to the internal diameter of the former ring, substantially as specified.

4. The combination, with a plug compris ing a core and a shell, of-a washer of 1nsulating material supported from said shell, a frustoconical metallic body mounted on the outer end of said core and having therein a pair of spaced annular washers of insulating material, the lower of said washers being below the first-mentioned washer and the upper of said washers being located above the first-mentioned washer, the outer diameter of the first-mentioned washer and the inner diameters of the other washers being substantially the same, substantially as specified.

In testimony whereof, I hereunto aflix my signature in the presence of two witnesses.

ARTHUR R. BULLOCK.

Witnesses:

A. J. HUDSON, S. E. Fours. 

